CREATE TABLE table_53404 ("Year" FLOAT, "Entrant" CLOB, "Chassis" CLOB, "Engine" CLOB, "Pts." FLOAT)

On what Year did Entrant Leyton House have a Chassis type of Leyton House CG911?
SELECT "Year" FROM table_53404 WHERE "Entrant" = 'leyton house' AND "Chassis" = 'leyton house cg911'
SELECT "Year" FROM "table_53404" WHERE "Chassis" = 'leyton house cg911' AND "Entrant" = 'leyton house'