user: Question: When did a Competition of Friendly, and a Score of 2–1, and a Venue of Philadelphia , Pennsylvania occur?
Columns: ['Date', 'Venue', 'Score', 'Result', 'Competition']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['May 28, 2005', 'Chicago, Illinois', '1–2', '1–2', 'Friendly match']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Competition" = 'Friendly' AND "Score" = '2–1' AND "Venue" = 'Philadelphia , Pennsylvania';