(As Korra, in her jammies, walks away from her battle with Amon, accompanied by Katara, Sokka, Bolin, Mako and Asami, Amon gets up and charges at her. She nonchalantly throws the orange in her hands at a nearby switch, causing Amon to plummet to his death towards the ground below.)
Korra: No second chances. I'm that sort of an Avatar.
"I'm Korra. I'm the Avatar. I'm the bridge between the living world and the spirit world and the master of all four elements. I and my previous past lives have maintained balance and order for 9,829 years, and I'm the woman who's going to save your lives and the lives of every other being on the planet...You have a problem with that?"
Basically think of the Avatar as the Doctor, but instead of regenerating, he reincarnates. He doesn't "remember" his past lives, but a part of the previous incarnations live on within the Avatar's soul so he (or she) can talk to them. It's really a great series.
Toph, Sokka, blimey! No, no, no, no, hold on. Wait there! I've got something to say. I've got something I had to tell you. Something important, what was it? No, no, no, hold on. Tch tch tch tch... Oh, I know! Happy Avatar Day!
Hahaha ok this is a little funny , however I just cannot compare the Ninth Doctor to Aang. Yes they do kinda have the same look, but their personalities don't match at all IMO. Still funny though. See Katara? You should have gone with Zuko.
But. Thats not how it works in Avatar lore. Korra would be a baby or young child and she would not regenerate. And she deffinately would not pick up his last sentence. I know its a mashup joke but my inner fandom couldn't sit idley by lol. The artwork is pretty sweet though. So kudos