Please provide more context! "Johnny" could refer to many people, and without knowing which "Johnny" you're referring to, it's impossible to know what school his kids might attend.
Please tell me:
* Who is Johnny? Is he a celebrity, a character from a book or movie, or someone you know personally?
* How many kids does Johnny have?
* Where does Johnny live?
With more information, I can try to help you find the answer.