I really like playing 1v1 champs but I don't know which of them is the best or whatever

my favorite is Fiora but im not sure if she is really "the best"

who is your favorite?

Udyr

I don't really think of Udyr as a duelist but I guess if played and built right he could be. I will have to try that

Jax is the original best duelist ever. He still reigns supreme, being the only one to beat you to death with a street appliance instead of the usual sword, spear or crossbow. In seriousness, he's solid and snowballs hard.

Malzahar's the best mage duelist that isn't an anti-mage or assassin. The highest potential burst damage among mages (yes, it's over 5 seconds but he has long enough cooldowns to call it burst).

Vayne is the best duelist among carries. Her single-target DPS rivals Jax when she's built up, and she's one of the more recent champions to have a steroid that lasts longer than 10 seconds.

Jax is and always will be the best duelist. He was made to dominate 1v1 fights and nothing short of that really.

There's also Renekton, who, as opposed to simply winning 1v1s, was made to win top lane and nothing really short of that, but he comes close enough.

Trundle. The stronger you are the stronger he becomes against you.