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_35478 ( "Exit date" text, "Pos." text, "Player" text, "To club" text, "Transfer fee" text )

### Question ###
What is the exit date of the player who transferred to Portsmouth?

### Accurate SQL ###

SELECT "Exit date" FROM table_35478 WHERE "To club" = 'portsmouth'