Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_42 ( entrant VARCHAR, year VARCHAR, chassis VARCHAR, points VARCHAR )

### Question ###
What is the entrant of a chassis maserati 250f, also has 6 points and older than year 1957?

### Accurate SQL ###

SELECT entrant FROM table_name_42 WHERE chassis = "maserati 250f" AND points = "6" AND year < 1957