CREATE TABLE table_204_939 (id DECIMAL, "year" DECIMAL, "chassis" TEXT, "engine" TEXT, "start" TEXT, "finish" TEXT)

in what year did the buick engine start in 1st ?
SELECT "year" FROM table_204_939 WHERE "engine" = 'buick' AND "start" = 1
SELECT "year" FROM "table_204_939" WHERE "engine" = 'buick' AND "start" = 1