From Zelda Legends Wiki
Gerudo Valley doesn't have many enemies there, but the nastiest are the Leevers crawling around. The Leevers can be defeated by first drawing them close to Link with Hookshot or Clawshot, and then attacking them with a sword.
The valley is located in different places in The Legend of Zelda: Ocarina of Time and The Legend of Zelda: Twilight Princess. The Gerudo Valley is at the upper left corner in Ocarina of Time, and it's located right side of Hyrule in Twilight Princess.