CREATE TABLE table_name_33 (attendance INT, opponent VARCHAR, date VARCHAR)

What was the attendance on 31 January 2009 when the opponent was Airdrie United?
SELECT AVG(attendance) FROM table_name_33 WHERE opponent = "airdrie united" AND date = "31 january 2009"
SELECT AVG("attendance") FROM "table_name_33" WHERE "31 january 2009" = "date" AND "airdrie united" = "opponent"