Minato has never been hit, whereas A and Tobi have. I think that pretty much answers your question.
A was hit by Sasuke with a regular old chidori, now that is embarrassing. He was also kicked in the back by Minato.
Tobi has been hit by; Konan, Minato, Torune, Itachi (via the Amaterasu in Sasuke's eye), Naruto and Suigetsu. That's right, you guys forgot about that time that Tobi blocked Suigetsu's sword with his arm. (it doesn't really count I know but still he has been hit the most)
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thought i agree that minato win this avoiding contest match