user: Question: What is the Nation with a Date that is May 6, 1991?
Columns: ['Record', 'Athlete', 'Nation', 'Venue', 'Date']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['4.02 m', 'Marc Wright', 'United States', 'Cambridge , U.S.', 'June 8, 1912']
SQL:

assistant: SELECT "Nation" FROM "Table" WHERE "Date" = 'May 6, 1991';