Are you looking to set a fixed duration for the Sequence in the same way we set a duration for a Comp in After Effects? If so, that's not an option in Premiere Pro. The Sequence is as long as the last frame of your last clip in the Timeline with time for up to 24 hours.
If you need to keep the duration of your edit to 10 seconds, you just fill 10 seconds with source footage.
You could place a Timeline Marker where you want the edit to end or use a 10 second clip as a guide to verify visually that your duration is 10 seconds.