Write SQL query for below result set

drop table if exists citydistance 
create table citydistance 
(
city1  varchar(100),
city2  varchar(100),
distanace int
)


insert into citydistance values ('Delhi','Mumbai',5000)
insert into citydistance values ('Mumbai','Delhi',5000)
insert into citydistance values ('Lucknow','Delhi',600)
insert into citydistance values ('Delhi','Lucknow',600)
insert into citydistance values ('Mumabi','Goa',200)
insert into citydistance values ('Goa','Mumabi',200)
insert into citydistance values ('Goa','Delhi',800)
insert into citydistance values ('Delhi','Goa',800)
insert into citydistance values ('Lucknow','Mumbai',800)
insert into citydistance values ('Mumbai','Lucknow',800)
insert into citydistance values ('Hydrabad','Lucknow',1800)

If you see in above table Delhi to Mumbai distance is 5000 while another entry of Mumbai to Delhi is also with 5000, so we want only one entry for Delhi to Mumbai with 5000 distance OR Mumbai To Delhi with 5000 distance, Any single entry in output is fine.
But in case of hydrabad to Lucknow, we have single entry, so single entry will come on output

city1		city2		distanace
Delhi		Mumbai		5000
Lucknow		Delhi		600
Mumabi		Goa			200
Goa			Delhi		800
Lucknow		Mumbai		800
Hydrabad	Lucknow		1800