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_56 (part_number_s_ VARCHAR, l2_cache VARCHAR, frequency VARCHAR)

### Question ###
What's the part number of the processor that has an 1.8 ghz frequency and 2 × 256 kb L@ Cache?

### Accurate SQL ###

SELECT part_number_s_ FROM table_name_56 WHERE l2_cache = "2 × 256 kb" AND frequency = "1.8 ghz"