user: Question: What is the chassis of Officine Alfieri Maserati with a Maserati Straight-6 engine and fewer than 6 points?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1951.0, 'Scuderia Milano', 'Maserati 4CLT/48', 'Maserati Straight-4', 0.0]
SQL:

assistant: SELECT "Chassis" FROM "Table" WHERE "Engine" = 'Maserati Straight-6' AND "Entrant" = 'Officine Alfieri Maserati' AND "Points" < 6.0;