CREATE TABLE table_203_506 (id NUMBER, "opponent" CLOB, "played" NUMBER, "won" NUMBER, "lost" NUMBER, "drawn" NUMBER, "% won overall" CLOB)

who did they have the largest win/loss differential against ?
SELECT "opponent" FROM table_203_506 ORDER BY ABS("won" - "lost") DESC LIMIT 1
SELECT "opponent" FROM "table_203_506" ORDER BY ABS("won" - "lost") DESC FETCH FIRST 1 ROWS ONLY