Find the different first names and cities of the students who have allergy to milk or cat.
SELECT DISTINCT T1.fname ,  T1.city_code FROM Student AS T1 JOIN Has_Allergy AS T2 ON T1.stuid  =  T2.stuid WHERE T2.Allergy  =  "Milk" OR T2.Allergy  =  "Cat"
different first names refers to DISTINCT T1.fname; cities refers to T1.city_code; students who have allergy to milk or cat refers to WHERE T2.Allergy = 'Milk' OR T2.Allergy = 'Cat';