CREATE TABLE table_69681 ("Year" FLOAT, "Entrant" TEXT, "Chassis" TEXT, "Engine" TEXT, "Points" FLOAT)

What is the earliest year that had a Lotus 49B chassis?
SELECT MIN("Year") FROM table_69681 WHERE "Chassis" = 'lotus 49b'
SELECT MIN("Year") FROM "table_69681" WHERE "Chassis" = 'lotus 49b'