I've been following her career and I read far too many opinions about Gaga being "ugly", which means, not fitting the beauty standards. I believe the ascendant can be shown by how we are perceived, so, if she is generally perceived as not a classic beauty, this rules out Libra rising and Venus on ascendant, imo.
There was a lot of talk about her possibly being a transgender, hermaphrodite, all sorts of talks about Gaga having a penis, which obviously is tabloid ****, but till now the whole incident gives rise to a lot of jokes about "tuck games" and other stuff that imply that she has a penis. So, I'm guessing Aries or Mars on ascendant.
Her Mars is in between Sagittarius and Capricorn, and is conjunct Uranus in Sagit and Neptune in Cap. I'm guessing this combo can be around her ascendant, since she was perceived as someone with masculine traits (Mars) and her public persona is a shape-shifter (Neptune) and eccentric to the extreme (Uranus).
Late Sagittarius or early Capricorn is my guess. That would send Libra straight to her midheaven, which would indicate an artistic career, with ruler Venus angular in the 4th in Aries.
Also Mercury in Pisces in the 3rd (voice, communications), and Moon in the 10th.
(I'm not sure if I like her. I find her ambition and drive interesting, and she presents herself as an inovator, but I think her music is everything but groundbreaking...............)