No difference between clear and UV for a dSLR. Well...I can't speak for all of them, but I can speak for the 7D and 5DII that I empirically tested with both short- and long-wave UV light sources - both were insensitive to UV.
Out of curiosity, how did you perform your test?
...and...again, out of curiosity, are there any dSLRs that are
sensitive to UV? I'm thinking that, if so, there might be interesting applications for, for example, getting a filter that blocks all but UV. I understand that there are flowers that are much more interesting in the UV spectrum than the visible spectrum....
In a similar vein, I'm also somewhat surprised that IR-blocking filters haven't become popular for DSLRs. Blown red channels when shooting certain subjects at least used to be a common problem, and that was because the cameras had some sensitivity to IR. Modern cameras have better IR-blocking filters built into the sensor, but for a time there, IR contamination was at least as big a problem for digital shooters as UV contamination ever was for film.