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_19359427_6 ( date_of_vacancy VARCHAR, team VARCHAR )

### Question ###
When did the old manager vacate his position in Plymouth Argyle?

### Accurate SQL ###

SELECT date_of_vacancy FROM table_19359427_6 WHERE team = "Plymouth Argyle"