I recall Supreme Kai having the power to cause paralysis to his targets as seen when he stopped a SSJ2 powered Gohan from attacking two of Babidi's cronies during the Tenkaichi Budokai at the start of the Majin Buu saga. If he can connect with that ability on Vegita, then the Saiyan prince is easy pickings for Supreme Kai. On the other hand, Vegita in Cell Saga era was a Second-Grade SSJ and gods in the world of DBZ tend to be weaker than SSJ-powered Saiyans. So at the moment, I can't say who I want to put my money on.
I think Vegeta might have him. During the Debora fight Vegeta comments that the SSJ2 Gohan that the Kia stops is much weaker than when he fought Cell. Also Supreme Kai was a pansy even after he fused into Kiabeto.
Yeah I would probably go with Vegeta. The paralysis thing is interesting though. I suppose it depends of if Supreme Kai can use other abilities while using the paralysis, we have only ever seen him doing the paralysis on it's own so we can't say for sure. It might require all his power or something.