it will be harry cause he defeated "You Know Who".

^ Which happened because of the Elder Wand only listening to Harry. Otherwise, I think Voldie would have killed him. Anyway, Hermione is the best in Transfiguration, Charms etc. while Harry only beats her in DADA. And since Harry isn't likely to use dark magic, I think Hermione would win this battle by far.

Hermione would defeat them both hands down

Well, yeah, the only one more powerful than Voldemort is Dumbledore, lol. And it took McGonagall, Kingsley, and Slughorn, all of whom are EXTREMELY powerful, to be equal to him.

But between the other two (which was the original intent of this poll), I see no reason why Hermione shouldn't win. Harry's only specific strengths are patronus charms and plot devices, neither of which will save him from a witch who actually has an extremely high level of skill.

While Hermione is better at book learning, exams and general memory, Harry is better and fighting magic. Hermione admitted this herself. That's why she suggested him as the DA's teacher.