CREATE TABLE table_204_155 (id NUMBER, "rank" NUMBER, "heat" NUMBER, "athlete" CLOB, "nationality" CLOB, "time" NUMBER, "notes" CLOB)

which country ranks the least ?
SELECT "nationality" FROM table_204_155 ORDER BY "rank" DESC LIMIT 1
SELECT "nationality" FROM "table_204_155" ORDER BY "rank" DESC FETCH FIRST 1 ROWS ONLY