An employer cannot ask you about arrests on a job application. They can only ask whether you have been convicted of a criminal offense. If your entire record has been sealed or expunged, you may answer "no" to the question "Have you ever been convicted of a crime?”
If you have convictions that you could not seal because they were ineligible, or were subject to a waiting period, you must still disclose those convictions.
It is illegal for an employer to discriminate against you in any way due to a sealed or expunged record.