CREATE TABLE table_15249 ("Year" FLOAT, "Entrant" TEXT, "Chassis" TEXT, "Engine" TEXT, "Pts." FLOAT)

What are the points for a chassis of march 811?
SELECT SUM("Pts.") FROM table_15249 WHERE "Chassis" = 'march 811'
SELECT SUM("Pts.") FROM "table_15249" WHERE "Chassis" = 'march 811'