CREATE TABLE table_20458 ("Game" FLOAT, "Date" CLOB, "Opponent" CLOB, "Result" CLOB, "Oilers points" FLOAT, "Opponents" FLOAT, "Oilers first downs" FLOAT, "Record" CLOB, "Attendance" FLOAT)

On Sept. 17, how many first downs did the oilers have?
SELECT COUNT("Oilers first downs") FROM table_20458 WHERE "Date" = 'Sept. 17'
SELECT COUNT("Oilers first downs") FROM "table_20458" WHERE "Date" = 'Sept. 17'