user: Question: What is the sum of Points, when Year is after 1959, and when Class is 250cc?
Columns: ['Year', 'Class', 'Team', 'Points', 'Wins']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1959.0, '125cc', 'Honda', 1.0, 0.0]
SQL:

assistant: SELECT SUM("Points") FROM "Table" WHERE "Year" > 1959.0 AND "Class" = '250cc';