Fellow Actors, should I audition for the role I know I’ll get or should I audition for the role I want?

I’m in highschool and we might have a production of Into the Woods. I’ve had my teacher on occasion make a comment that I’m perfect for the witch and I should play her. (She’d be the director) Though I want to play the bakers wife more than anything. So when it comes to auditioning, do I audition for the bakers wife or the witch? It would be hard to audition for both because they both sing differently and I’d have to pick a song that pushes my skills in singing like them.