Normally if you're importing from a database there'd be moves as well rather than just a position so you could simply look at the notation in the board window to determine it.
Assuming that's not the case than that there are still at least two ways.
1. Ensure the "home" tab is clicked at the top (it's usually on there by default) and press "infinite analysis" button, and see which side the engine starts to calculate for.
2. Press "S" to take you into positon set up and it will tell you who is currently on move.
I've recently started using Fritz 13 and one thing seems to be missing - the board has no indication of side to move. For example in other chess software there is a white/black dot at board corner for this purpose. I was looking in Fritz board design options but didn't find anything. So when I load a position from database how do I know if it's white's or black's move?