If you look in variants.h in the moteino samd\_version_\variants\moteino_zero you will find the following mapping:
/*
* Analog pins
*/
#define PIN_A0 (14ul)
#define PIN_A1 (15ul)
#define PIN_A2 (16ul)
#define PIN_A3 (17ul)
#define PIN_A4 (18ul)
#define PIN_A5 (19ul)
#define PIN_DAC0 (14ul)
Where the numbers are actual digital pin numbers. So 14ul is D14 or A0.