He fails in both rounds. Even wit all Akuma's might, he wouldn't be able to seriously harm Demitri. He would at the very least have to be near Belial Warning Shot Level for round 1. Lol, and the SGS and SSGS would just send Demitri home. Given the fact that he can best powered down Pyron, I don't see what Akuma can do to survive.
Now, if it were CFE Akuma...that would be a brand new story altogether.