Table: usac_champ_car_race
Columns: rnd
date
race_name
length
track
location
type
pole_position
winning_driver

Question: Who had the pole position in the August 15, 1981 race? 
SQL: SELECT "pole_position" FROM usac_champ_car_race WHERE "date" = 'August 15, 1981'

Question: Which track was used on September 12, 1981? 
SQL: SELECT "track" FROM usac_champ_car_race WHERE "date" = 'September 12, 1981'