So Leon is nearly 4x stronger than Aki, which is big, granted Aki fights folks much stronger than he is, so it doesn't matter. Aki also has a pretty huge durability advantage thanks to his suit. Leon will need to target his head if he wants to win, which is easier said than done when Aki's precognition has let him react to all of Leon's attacks. One hit from Aki also means death via his High 8-C sword.
Leon's only shot here is his flashbangs and P.R.L 412 being able to disorient Aki and create an opening for a head shot, but that requires Leon to keep a fair distance, or else he will also be disoriented.
Voting Aki here, he will much more easily close the distance and make Leon unable to use his wincons and eventually cut him down.