user: Question: What is the highest year premiered when Benjamin Castaldi is main presenter?
Columns: ['Region/Country', 'Local name', 'Main presenter', 'Network', 'Year premiered']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['China', '夢想合唱團 Mengxiang hechang tuan', 'Sa Beining', 'CCTV-1', 2011.0]
SQL:

assistant: SELECT MAX("Year premiered") FROM "Table" WHERE "Main presenter" = 'Benjamin Castaldi';