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

### Question ###
Find the first names of the teachers that teach first grade.

### Accurate SQL ###

SELECT DISTINCT T2.firstname FROM list AS T1 JOIN teachers AS T2 ON T1.classroom = T2.classroom WHERE grade = 1