Deborah by a long shot.
Debra is a creative spelling invented during the name's spike in popularity in the 1950s, and therefore is an example of "dated trendiness".
Deborah, on the other hand, is the traditional spelling, and stands the test of time. You should spell the name
Deborah if you plan on using the name these days. By the way,
Deborah is one of those dated names that I like so much!