user: Question: What is the Date of Issue with a Theme with Mental Health?
Columns: ['Date of Issue', 'Theme', 'Design', 'Illustration', 'Paper Type', 'First Day Cover Cancellation']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['5 January 2008', 'Year of the Rat', 'Tandem Design Associates', 'Harvey Chan', 'Tullis Russell Coatings', 'Vancouver, BC']
SQL:

assistant: SELECT "Date of Issue" FROM "Table" WHERE "Theme" = 'Mental Health';