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_16 (year_named INTEGER, name VARCHAR, diameter__km_ VARCHAR)

### Question ###
What's the average year for the name aida-wedo dorsa with a diameter less than 450?

### Accurate SQL ###

SELECT AVG(year_named) FROM table_name_16 WHERE name = "aida-wedo dorsa" AND diameter__km_ < 450