You cannot do that directly from either the PIX command line or ASDM. Even if you weren't running 10 year old software on a product that's been long-discontinued you'd need some external resources.
Typically we use either Cisco Security Manager (CSM) or an external syslog server if we need this sort of data.
The Pix can generate the syslog messages of VPN user logon and logoff but local storage is very limited so you cannot get the historical data from looking at the local syslog messages.