CREATE TABLE table_42035 ("Year" FLOAT, "Competition" CLOB, "Venue" CLOB, "Position" CLOB, "Event" CLOB, "Notes" CLOB)

Which Year that has Notes of dnf?
SELECT MIN("Year") FROM table_42035 WHERE "Notes" = 'dnf'
SELECT MIN("Year") FROM "table_42035" WHERE "Notes" = 'dnf'