There are at least a couple of ways to do this.....3 I can think of, but none easy to explain. I know I've seen a tutorial recently, but don't remember enough to be able to find it.
The easiest way might be to use Object menu > Arrange > Polar Coordinates tab. I have not had good luck with that feature. When I was trying it just now, I couldn't get it to work. And then all of a sudden, it was working. So no guarantees. But here are the steps:
Draw a 3rd circle which is precisely between the 2 original circles. Do not convert this circle to path. Hold the Ctrl key, and rotate the circle counterclockwise by 4 steps. There's no visual clue, so you have to look at the status bar while you rotate. When the status bar indicates 60 degrees, stop rotating.
Type the numbers, one at a time, starting with 12 and ending with 1. It doesn't matter where you type them, but it is important to start with 12 and end with 1. I mean, make 12 separate text objects. Not one long string of numbers. (With Text tool, click, type 12, move over, click, type 11, move over, click, type 10, etc.)
I had to move my circle, to make it work (and I'll report it on the mailing list later, in case it might be a bug). So if the result puts the numbers all at 3 o'clock, you could try selecting all 3 circles, and move them together.
In the Polar Coordinates tab, choose "Object's rotational center" and "First circle" (works just as well with 2nd circle). Select all the numbers and the newly rotated 3rd circle, then click the Arrange button.
If you want the numbers to be rotated according to their position around the circle, so that 6 is upside-down (I've seen some clocks like that), be sure to tick the Rotate option in the dialog before you click Arrange.
Now to deal with the 3rd circle, which you probably don't want to see. If you don't think you'll ever need the circle again, you could just delete it. Or if you might need to use it again, you can either note what size it is, so you can make another later, or you could keep the circle and give it either zero width or make it transparent, so it's still in the file. Or you could move it to a hidden layer.
Let us know if you run into any problems, and we'll try to help