What champion, at level 6, with no items, is the best?

I was thinking about this last night and I would like to know what you guys think. So basically what I'm asking is that any given champion hits level 6 and has no items, who would be the best? Like who wouldn't lose to another champion? Only using abilities, auto attacks and base damage. No ignite, heal, etc.

The first champion that came to mind was Anivia, high burst damage early on and a respawn after initial death, assuming they can't kill you off while in egg form. Dr. Mundo also comes to mind with his immense healing from his ult and cleavers of death.

If you can't picture what I'm thinking of, picture this. Basically two champions in ARAM, no minions, they meet in the middle and cast abilities and auto attacks until one of you die.

What are your thought and why? Feel free to counter anyone's choice with a valid response.