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_203_89 ( id number, "#" number, "name\n(birth-death)" text, "took office" text, "left office" text, "monarch" text, "prime minister" text )

### Question ###
how many consecutive years did ernest george jansen serve as governor general of the union of south africa ?

### Accurate SQL ###

SELECT "left office" - "took office" FROM table_203_89 WHERE "name\n(birth-death)" = 'ernest george jansen'