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_74 ( employed VARCHAR, position_held VARCHAR )

### Question ###
What are the years employed shown for mathematics & prefect master?

### Accurate SQL ###

SELECT employed FROM table_name_74 WHERE position_held = "mathematics & prefect master"