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_67 ( controller VARCHAR, nand_type VARCHAR, seq_read_write_mb_s VARCHAR )

### Question ###
Which controller is NAND type 25nm mlc-het with sequential read/write MB/s of 270/210?

### Accurate SQL ###

SELECT controller FROM table_name_67 WHERE nand_type = "25nm mlc-het" AND seq_read_write_mb_s = "270/210"