If I'm a convicted felon and 6 years after my conviction I had it expunged, do I still have to answer "Yes" on a job application if ive been convicted on a felony?

In California, you do NOT have to answer yes. Provided the misdemeanor or felony was properly expunged, in California one may legally and truthfully state on an application that he has not been convicted as to the expunged crime.  

Note, however, that there is an exception to this rule if you are applying to be a peace officer or running for public office. The exception also applies to those seeking work at the California Lottery Commission or applying for a state license. 

Separately, by law, an expungement makes it so that a California employer may NOT use your record against you in deciding to hire you or in deciding to give you a promotion.