"Το μεταπτυχιακό και το διδακτορικό."

[doconnor80]

The 'masters' and the PhD should be accepted (not 'master')

[jaye16]

It has been corrected thank you for the input.

[daph03ne]

In the states, "graduate degree" would be more common than "postgraduate degree" and means the same thing (degree after university/college)