user: Question: Name the date that has a Friendly competition at Rheinpark Stadion, Vaduz
Columns: ['Date', 'Venue', 'Score', 'Result', 'Competition']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['30 April 2003', 'Rheinpark Stadion , Vaduz', '1–0', '1–0', 'Friendly']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Competition" = 'Friendly' AND "Venue" = 'Rheinpark Stadion, Vaduz';