Ok well since the Dark thing is cleared up i realized.
Darth Vader. He will choke Yoda before he can come with in 20 feet. Then why Yoda is on the ground, Vader will electrocute him, since by now Yoda is pretty much fucked, he will just chop Yoda in half. Done.
BTW: My all time favorite star wars character has got to be Anakin Solo. (For those of you who are totally, utterly, completely Star Wars geeks, like me).