Make sure that the motor power supply will handle the stall current of the pump motor. Stall current is drawn, briefly, every time the motor starts. Stall current can be 10 or more times the running current. The stall current should be listed in the motor data sheet.
The L293 or L298 will waste a significant amount of your battery power as heat. A MOSFET motor driver is much more efficient. Use a logic level N channel MOSFET. The MOSFET, also, must be able to handle the motor stall current.
