CREATE TABLE table_name_4 (date VARCHAR, venue VARCHAR, competition VARCHAR, score VARCHAR)

When did a Competition of friendly, and a Score of 2 1, and a Venue of philadelphia , pennsylvania occur?
SELECT date FROM table_name_4 WHERE competition = "friendly" AND score = "2–1" AND venue = "philadelphia , pennsylvania"
SELECT "date" FROM "table_name_4" WHERE "2–1" = "score" AND "competition" = "friendly" AND "philadelphia , pennsylvania" = "venue"