To maintain code, UL et al compliance, and insurance coverage, you have to follow the manufacturer's instructions.
If the unit is 240V, the 13 amps are not split between the legs. 13 amps comes in, 13 amps goes out. (Actually, it's the same for 120V, but only one leg.)
The model number posted has an instruction manual, which says:
1）Must follow the electric safety regulations when
installing the unit.
2）According to the local safety regulations, use
qualified power supply circuit and air switch.
3）Make sure the power supply matches with the
requirement of air conditioner.
Though the instructions do not apparently state the circuit breaker size, and the table for wire size does say a 13-amp load should have a 1.5 sq mm wire size (a little less than 14 gauge) point 1 says electrical code should be followed.
NEC requires circuits feeding long-term heavy-draw devices to be de-rated 80%:
15-amp circuit = 12 amps max de-rated
20-amp circuit = 16 amps max de-rated
Since the unit has 13 Amps draw, a 20 amp breaker would be used, with 12-gauge wire to the unit.
(NEC requirements are deduced from "KM DIY Home"'s mention of split-leg power supply and the 80% rule. If this deduction is not accurate, the local authority should be followed.)