CREATE TABLE table_18020 ("Week" FLOAT, "Date" CLOB, "Opponent" CLOB, "Result" CLOB, "Game site" CLOB, "Record" CLOB, "Attendance" FLOAT)

Who did the Seahawks play on September 4, 1983?
SELECT "Opponent" FROM table_18020 WHERE "Date" = 'September 4, 1983'
SELECT "Opponent" FROM "table_18020" WHERE "Date" = 'September 4, 1983'