CREATE TABLE table_203_5 (id NUMBER, "season" CLOB, "competition" CLOB, "round" CLOB, "opponent" CLOB, "home" CLOB, "away" CLOB, "aggregate" CLOB)

does each competition have an opponent listed ?
SELECT COUNT(*) > 0 FROM table_203_5 WHERE NOT "opponent" IS NULL
SELECT COUNT(*) > 0 FROM "table_203_5" WHERE NOT "opponent" IS NULL