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_19526911_1 (arena__capacity_ VARCHAR, head_coach VARCHAR)

### Question ###
What is the arena capacity of the arena in the town whose head coach is Roberto Serniotti?

### Accurate SQL ###

SELECT arena__capacity_ FROM table_19526911_1 WHERE head_coach = "Roberto Serniotti"