[gnode]

Yes, you should ask for one. Be straightforward when asking, and make the case that you're now a more valuable member of the company. Cite that you've become the de-facto project leader. You could also say you want a promotion, or at least a change in title, if you feel you are no longer in the junior role.

You may also want to take into account the political situation in your company. Who makes decisions on raises and promotions? Is there a process in place? Is what you do visible to them (and how could it be more visible)?