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 teachers ( lastname text, firstname text, classroom number )
TABLE: CREATE TABLE list ( lastname text, firstname text, grade number, classroom number )

### Question ###
Find the last names of teachers teaching in classroom 109.

### Accurate SQL ###

SELECT lastname FROM teachers WHERE classroom = 109