Read saved data

Dear all,
after a "Save Data" action, I would like to read the value of an autoincrement field.
Using debug, I have found:[pre] ...
[log] => Array
(
[0] => INSERT INTO `trodb_chronoforms_data_subscriptionForm` (`name`, `surname`, `gender`, `birthday`, `taxCode`, `address`, `province`, `municipality`, `zip`, `email`, `phone`, `statementAccept`, `privacyAccept`, `requestAdmission`, `money`, `payment`, `created`, `user_id`) values ('Pinco', 'Pallino', 'M', '15/08/1970', 'PNCPLL15M70H501A', 'via da qui, 3', 'RO', 'Adria', '45011', 'secret@email.com', '33312345678', 'si', 'si', 'si', '30', 'Transfer', '2018-10-13 15:44:39', '296');
)

[var] => Array
(
[name] => Pinco
[surname] => Pallino
[gender] => M
[birthday] => 15/08/1970
[taxCode] => PNCPLL15M70H501A
[address] => via da qui, 3
[province] => RO
[municipality] => Adria
[zip] => 45011
[email] => secret@email.com
[phone] => 33312345678
[statementAccept] => si
[privacyAccept] => si
[requestAdmission] => si
[money] => 30
[payment] => Transfer
[created] => 2018-10-13 15:44:39
[user_id] => 296
[strong] [aid] => 40[/strong]
[/pre]
I'm interested in "aid" value (40 in my sample).
How to get it?
Neither {var:aid} nor {data_save48:var.aid} returns requested value

Could you help me?[br]Regards