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_64456 ( "Kanji" text, "Name" text, "Builder" text, "Laid down" text, "Launched" text, "Completed" text )

### Question ###
when was the ship completed when laid down is 21 august 1925?

### Accurate SQL ###

SELECT "Completed" FROM table_64456 WHERE "Laid down" = '21 august 1925'