Newer versions of Joomla store the version of the database schema in the table jos_schemas (You have to replace jos_ with your database prefix). Look in the row wehere the extension ID is 700. For example it could read:
extension_id|version_id
700 |1.7.3-2011-11-10
This would indicate that the last Joomla version this database was used with was 1.7.3. (The date behind it is the day the change to the database schema was committed).
This system has been in place at least since Joomla 1.7. For older versions you'll have to resort to different solution. The database schema between version 1.0, 1.5 and 1.6 is very different so it should not be very hard to figure out to which version it belongs by comparing to other installations.
Joomla 1.0 and 1.5 did not change the database schema in minor versions so you can always install the newest minor version of those. Joomla 1.7 and newer will update the database schema themselves if they discover it's outdated, however I wouldn't rely on this when restoring a site.
Lastly your reference to Joomla Pack makes me think you're still using Joomla 1.0 - update! It's an incredibly outdated version.