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_4 (used VARCHAR, power__hp_ VARCHAR, engine VARCHAR)

### Question ###
When was power (hp) less than 93 for the OM324 engine used?

### Accurate SQL ###

SELECT used FROM table_name_4 WHERE power__hp_ < 93 AND engine = "om324"