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_29138 ( "Team" text, "Outgoing manager" text, "Manner of departure" text, "Date of vacancy" text, "Incoming manager" text, "Date of appointment" text, "Position in Table" text )

### Question ###
Who is the incoming manager when the date of vacancy was 21 march 2011?

### Accurate SQL ###

SELECT "Incoming manager" FROM table_29138 WHERE "Date of vacancy" = '21 March 2011'