สนามกีฬาใดมีผู้เข้าชมเฉลี่ย 13,840 คน?ไม่จำเป็นต้องใช้ทุกโต๊ะ
Which stadiums have an average attendance of 13840?It is not neccessary to use all the tables.
 table_11208143_9:  stadium [ VARCHAR]  average [ VARCHAR] 
SELECT stadium FROM table_11208143_9 WHERE average = 13840