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_21 (authority VARCHAR, area VARCHAR, gender VARCHAR, decile VARCHAR)

### Question ###
Which Authority has a Gender of coed, a Decile smaller than 6, and an Area of merivale?

### Accurate SQL ###

SELECT authority FROM table_name_21 WHERE gender = "coed" AND decile < 6 AND area = "merivale"