Here is an example of the query and the expected output of convert-timezone
(mt/with-report-timezone-id "UTC"
(mt/with-driver :postgres
(mt/dataset test-data
(->> (mt/run-mbql-query
users
{:expressions {"login_in_HCM" [:convert-timezone [:field (mt/id :users :last_login) nil] "Asia/Ho_Chi_Minh" "Europe/Rome"]
"hour_login_in_HCM" [:get-hour [:expression "login_in_HCM"]]}
:fields [[:expression "login_in_HCM"]