NTSC and PAL is only relevent if you are burning your video to a disc, which is mentioned in the help.
"Timeline frame rate: select the TV format (NTSC or PAL) and frame rate for your video production. The format should correspond to the region in which you plan to play your video (if you burn it to disc). The frame rate should correspond to the source video footage being used in your production."
If your video is strictly digital, then it doesn't matter that much. Except they should be consistent.
Ash