-- Database schema
| list : LastName [ TEXT ] primary_key , FirstName [ TEXT ] , Grade [ INT ] , Classroom [ INT ] | teachers : LastName [ TEXT ] primary_key , FirstName [ TEXT ] , Classroom [ INT ] |
-- -- Find the last names of all the teachers that teach GELL TAMI.

SELECT T2.lastname FROM list AS T1 JOIN teachers AS T2 ON T1.classroom  =  T2.classroom WHERE T1.firstname  =  "GELL" AND T1.lastname  =  "TAMI";