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_30 (function__percentage VARCHAR, estimated_function__percentage VARCHAR)

### Question ###
What is the function percentage when the estimated function percentage is 20?

### Accurate SQL ###

SELECT function__percentage FROM table_name_30 WHERE estimated_function__percentage = 20