CREATE TABLE table_name_56 (part_number_s_ VARCHAR(255), l2_cache VARCHAR(255), frequency VARCHAR(255))
What's the part number of the processor that has an 1.8 ghz frequency and 2 × 256 kb L@ Cache?
    
SQL: SELECT part_number_s_ FROM table_name_56 WHERE l2_cache = "2 × 256 kb" AND frequency = "1.8 ghz"