No. Just, no.
With a scheduled course, students are entitled to your undivided attention during the class meeting time. This may even be an accreditation requirement. There is no way you can teach two different classes at the same time.
Here are possible explanations I can think of (incorporating some from comments):
It is just a mistake.
One of the courses is planned to be cancelled or rescheduled, and the official schedule has not yet been updated to reflect it.
The two courses are actually the same course, cross-listed under two different numbers. Students registered for either one would all attend the same lectures, except one set of them would also come on Tuesdays while the others wouldn't (possibly a lab or something like that?). This is possible, for instance, if the two courses are on identical topics but are listed under different departments, or at different undergraduate/graduate levels.
They actually meet during different ranges of dates, which may be listed somewhere that you didn't notice.
One or both courses are asynchronous online courses or something of the kind, whose "meeting times" are fictitious and may just be assigned for some technical reason.
Either way, you should immediately contact the people responsible for scheduling. If there's a mistake, it needs to be fixed ASAP before more confusion results. And in any case, you need to know what you will actually be teaching.
(University schedules, though they look very precise and formalized, are often created with more human effort and fewer automated checks than most people might guess. Funny story: My first semester at my current job, there was another faculty member with a similar name to mine, and due to an autocomplete mistake, they assigned all of his classes to me, on top of the ones I was actually supposed to teach. So I was pretty startled when I checked the schedule and found my teaching load was more than double what I had been told - and most of them not even in my subject area! But of course it was obvious that it was a mistake, and it was fixed quickly when I reported it.)
Hypothetically if I do not report this schedule conflict, who will likely bear the blame? I, or the dean, or the department chair, or the one who made the schedule?
All of you - there's plenty of blame to go around. And in general, every employee of an organization has a duty to respond to potential problems that come to their attention, by reporting them through appropriate channels.
But for you in particular, I will bet a lot that if you search your email inbox, you'll find that at some point you received an email from a superior saying "Here is the proposed schedule for next semester; please check the courses assigned to you and report any issues right away". So if you deliberately fail to report the error you discovered, you've disobeyed a direct instruction. In some settings that could be a firing offense.
This is your responsibility and you can't evade it. I really hope that question is purely hypothetical, and not something that you seriously considered for even a moment.
