No. You would get 50,000 xp. It used to be that way but they've changed it since most people who ascended were level 20 already and it gave them no bonus.
alright thanks, btw does anyone have a good way to beat the doppleganger as a ranger in under 50 seconds anyways?
6 spirits (something that doesn't harm you or help it), poison arrow and powershot. At least, that's what I used both times I ascended my ranger. Works well.