CREATE TABLE table_204_617 (id DECIMAL, "date" TEXT, "opponent#" TEXT, "rank#" TEXT, "site" TEXT, "tv" TEXT, "result" TEXT, "attendance" DECIMAL)

who was the first opponent faced by the sooners in september 1971 ?
SELECT "opponent#" FROM table_204_617 WHERE "date" = 9 ORDER BY "date" LIMIT 1
SELECT "opponent#" FROM "table_204_617" WHERE "date" = 9 ORDER BY "date" NULLS FIRST LIMIT 1