Momo and Izuku get really into the post-match assessments during the Heroes vs. Villains exercise, leading to them unintentionally dominating the first discussion — which, since the first match involved them going against each other, leads to them picking apart each other's tactics... and derailing into discussing the finer points of their respective costumes.
When it comes time for Class 1-A to determine who their Class President will be, it turns into a landslide vote... for Hiyamizu-kun's dog, Hiro. Tenya is fit to be tied by the results.
You must feel for the poor boy- Tenya in canon lost, but he could at least understand why he lost to other classmates. In this one he loses to a therapy animal.