CREATE TABLE table_66808 ("Year" FLOAT, "Tournament" CLOB, "Venue" CLOB, "Result" CLOB, "Extra" CLOB)

What extra has world championships as the tournament, and 1st as the result?
SELECT "Extra" FROM table_66808 WHERE "Tournament" = 'world championships' AND "Result" = '1st'
SELECT "Extra" FROM "table_66808" WHERE "Result" = '1st' AND "Tournament" = 'world championships'