What physics equation can be used to describe the suction created by displaced liquid?

Technically, there is no such thing as suction in physics. It is a condition where there is less pressure than the surroundings. Atmospheric pressure is about 14.7 pounds per square inch. The volume of liquid squeezed out of a bottle has to be replaced by a volume of some other matter thereby lowering the absolute pressure inside it. What we commonly refer to as a vacuum or suction is just a condition where the pressure is less than atmospheric.