CREATE TABLE table_23068 ("Previous season 2007/2008" CLOB, "Team" CLOB, "Town" CLOB, "Arena  ( capacity ) " CLOB, "Website" CLOB, "Head Coach" CLOB, "Foreign Players  ( max. 2 ) " CLOB)

What is the arena capacity of the arena in the town whose head coach is Roberto Serniotti?
SELECT "Arena (capacity)" FROM table_23068 WHERE "Head Coach" = 'Roberto Serniotti'
SELECT "Arena (capacity)" FROM "table_23068" WHERE "Head Coach" = 'Roberto Serniotti'