CREATE TABLE table_204_918 (id DECIMAL, "week" DECIMAL, "date" TEXT, "opponent" TEXT, "result" TEXT, "record" TEXT, "attendance" DECIMAL, "bye" TEXT)

did they only play the denver broncos once ?
SELECT (SELECT COUNT(*) FROM table_204_918 WHERE "opponent" = 'denver broncos') = 1
WITH "_u_0" AS (SELECT COUNT(*), 'denver broncos' AS "_u_1" FROM "table_204_918" GROUP BY 'denver broncos') SELECT COALESCE("_u_0"."", *) = 1 LEFT JOIN "_u_0" AS "_u_0" ON "_u_0"."_u_1" = "opponent"