I am unemployed. Do I have to put $0 as "current salary" on a job application?

I am applying for a job in which a required field of the application is “current salary.”

I am unemployed. I am still receiving severance equal to the pay I was receiving at the end of my employment at my last job. I’m wondering if I can put what my salary was at the end of my last job, rather than putting $0 since I feel that would look bad. I don’t want to break a law or appear dishonest though.

Help.