Are you required to put a DUI on a job application if the DUI is nearly 20 years ago?

A DUI conviction on your DMV driving record NEVER goes away. Your driving record is a compilatioon of your entire driving history. To be safe you should include it. If it is 20 years old and you haven't had any subsequent offenses it probably won't count against you after all this time, AND you may possibly get points for honesty from a future employer.