CREATE TABLE table_name_71 (date VARCHAR2, competition VARCHAR2, venue VARCHAR2)

Name the date that has a friendly competition at rheinpark stadion, vaduz
SELECT date FROM table_name_71 WHERE competition = "friendly" AND venue = "rheinpark stadion, vaduz"
SELECT "date" FROM "table_name_71" WHERE "competition" = "friendly" AND "rheinpark stadion, vaduz" = "venue"