Table: agueda_subregion
Columns: name
area_km
pop
pop_area_1_km
no_p
no_c_no_t
subregion

Question: Which Subregion has a No P. of 4, and a Pop/Area (1/km²) of 534?
SQL: SELECT "subregion" FROM agueda_subregion WHERE "no_p" = 4 AND "pop_area_1_km" = 534

Question: Which Pop/Area (1/km²) has a No P. larger than 1, and a Name of albergaria-a-velha?
SQL: SELECT AVG("pop_area_1_km") FROM agueda_subregion WHERE "no_p" > 1 AND "name" = 'albergaria-a-velha'