CREATE TABLE table_204_639 (id NUMBER, "poll company" CLOB, "source" CLOB, "publication date" CLOB, "psuv" NUMBER, "opposition" NUMBER, "undecided" NUMBER)

which poll company has the most opposition ?
SELECT "poll company" FROM table_204_639 ORDER BY "opposition" DESC LIMIT 1
SELECT "poll company" FROM "table_204_639" ORDER BY "opposition" DESC FETCH FIRST 1 ROWS ONLY