Question: Which city's southern suburbs were the location of an electoral district which lost Labor-voting areas to Victoria Park, Canning and Welshpool, and became substantially safer for the major political party in Australia founded in 1945?
Sentence (from "Electoral district of Heysen"): It is a 1,102 km² electoral district that takes in some of the outer southern suburbs of Adelaide before fanning south-east to include most of the Adelaide Hills, as well as farming areas some distance from the capital.
Relevant evidence: No