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_6 (est VARCHAR, city VARCHAR, state_province VARCHAR, league VARCHAR)

### Question ###
In what year was the cfl team in edmonton, alberta established?

### Accurate SQL ###

SELECT est FROM table_name_6 WHERE state_province = "alberta" AND league = "cfl" AND city = "edmonton"