What happen if no spot instance are available ?

I'm going to use spot instance request on my production. But i have few questions about how it work at specific moments.

Here is my configuration : Auto-Scaling-Group : Min instance = 2 Max instance = 10 100% spot instance and minimum of 1 on-demand.

What happen when the ASG need to scale up and there is no spot instance available ? Will he wait for spot instance, or will he ask for a on demand instance until a spot is available ?