Here are some posts I did, comparing Lantus and Levemir:
lantus-and-levemir-comparison
basal-insulin-strength-or-duration
As Scotteric says, Levemir does not last as long. Is that good or bad? It depends on how you will use it and what you are looking for.
What I like about Levemir is that it is kind of like a pump, you can adjust your basal quickly. When using Levemir, I do it twice a day and can take different amounts all the time, so it is like a basal you can adjust. If I want to change, I only need to wait 12 hours and I can change. You can’t do that as easily with Lantus or Tresiba.
The duration depends on dose. For me it is 12 hours, but for you it may be longer or shorter.
I could give you an estimate of duration for you, but I’d need to get personal and ask how much your basal is and how much you weigh.
Or you can look it up here:
Here is the important sentence:
RESULTS:
Duration of action for insulin detemir was dose dependent and varied from 5.7, to 12.1, to 19.9, to 22.7, to 23.2 h for 0.1, 0.2, 0.4, 0.8, and 1.6 units/kg, respectively.
That sentence 
is horribly confusing.
So I tried to simplify it here 
. I think this is an easier way to view it:
| Dosage amount (units / kilogram) | Average duration |
|---|---|
| 0.1 units/kg | 5.7 hours |
| 0.2 units/kg | 12.1 hours |
| 0.4 units/kg | 19.9 hours |
| 0.8 units/kg | 22.7 hours |
| 1.6 units/kg | 23.2 hours |
By the way, make sure you convert your body weight to kilograms!