It is possible to leave Little Tiger dahlias in pots over the winter, but it is not recommended as they are not cold hardy, and may not survive the winter. Dahlias are typically considered tender bulbs, and they require special care to survive winter. It's best to store the tubers in a cool, dry, and dark place over the winter, such as a basement or a garage.
Before storing, remove the foliage and let the soil dry out completely. Place the tubers in a cardboard box or paper bag filled with dry peat moss or vermiculite. Check them periodically and discard any that show signs of rotting or disease.
However, if you do live in an area with a warmer climate, such as USDA zone 8 or higher, it is possible to leave the pots with dahlias outside over winter.