user: Question: What is Date, when Format is vinyl, and when Label is Mercury?
Columns: ['Date', 'Region', 'Label', 'Catalogue', 'Format']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['17 April 1982', 'UK', 'Bronze', 'BRON 539', 'vinyl']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Format" = 'vinyl' AND "Label" = 'Mercury';