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 (proposed VARCHAR, listed VARCHAR, county VARCHAR)

### Question ###
When was the site listed 03/31/1989 in rockingham county proposed?

### Accurate SQL ###

SELECT proposed FROM table_name_6 WHERE listed = "03/31/1989" AND county = "rockingham"