Deidara wins, unless this is letz stil Ishida.
I get the feeling that Ishida is going to receive a huge powerup in the manga soon (might even put him on Ichigo's level, we'll see). But for now I'd say he has a shot at winning this as he's a good matchup for Deidara (since he can spam projectiles and also fly).
Uryuu. He sets Deidara up for the trap he used on Szayel Apporo
Unlike Szayel Deidara isn't immobile. Now we lack postskip feats so are we going by preskip?
When last he fought with details given yes. He should be stronger than that now. We just haven't seen him do anything noteworthy sine the middle of the Arrancar arc.
Given powerscaling at the least postskip should be better than Deidara at worst case