Wizard of Oz audition?

My High School's next musical production is the Wizard of Oz. What would be a good audition piece for the part of Dorothy? I was thinking about singing God Help the Outcasts from The Hunchback of Notre Dame. Is this a good song choice for this role? Are there any songs that you would suggest? I can sing Mezzo-Soprano, and I do not want to do a song from the Wizard of Oz or Wicked or any other spin off like that. I am already singing Don't Rain on my Parade from Glee for my show choir audition. Thanks!