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_204_625 ( id number, "model" text, "availability" text, "introduced" text, "length of use" text, "last of whiteness" text )

### Question ###
crest 3d intensive professional effects and crest whitestrips 3d professional effects both have a lasting whiteness of how many months ?

### Accurate SQL ###

SELECT "last of whiteness" FROM table_204_625 WHERE "model" = 'crest whitestrips 3d professional effects'