To add to 'Khaila's info, they used the white costume in one season, and the more standard blue in the other. (Unless of course you were referring to the first woman seen, with the staff. She's Stargirl. Or the woman in the white costume with the cleavage hole. That was Galatea in JLU. Of course, Galatea was really just their version of Power Girl. Who is really just Supergirl from a different universe. Of course.)