No, its definitely Princess Leia.
When it came to the prophecy, Yoda believed it was the will of the force for the Jedi to be destroyed.
He then stated that if the force wants the Jedi back, it will guide the Skywalker children to either Obi-wan or Yoda himself. Thats why they went into Exile instead of joining the rebellion. They were waiting for the Skywalker children to seek them out.
So when they discuss whether or not he will fall, Yoda is saying there is another hope and she is Luke's sister.
The original movie is titled "A New Hope" and that hope is luke. Leia would be the new, second, hope.
But fortunately, Luke succeeds in what he was supposed to do and that was turn his father back to the light, having his father fulfill the prophecy by eliminating ALL the previous Jedi and ALL the Sith, leaving only Luke behind to teach the ways of the force.