Was the competition ranking based on a blinded test set?
If not, the none of the results of the competition are very strong evidence.
If yes, unless there was gross misconduct* the blinding by the competition provides strong evidence in favor of the best ranked result.
Thus, cite the best result with the publication about the competition. If you are uncomfortable, you can also cite e.g. the 3 best results known so far.
* E.g. the "best" result having been obtained by improper knowledge about the test set reference labels. That would likely cast doubt again on the reliability competition and in turn on its publication.
I'm looking at the competition as something like a ring trial/round robin. The evidence generated depends critically on the trust in the organizer.