Over here in the ACT, we have an official policy of "salt and peppering", i.e. spreading public housing out evenly across the city including in wealthy areas.
also, is it better to build public housing in expensive areas (which implies less housing for the same fixed budget), or build public housing at the lowest cost, maximal housing capacity (which implies going to lower cost areas).
In the United States, projects applying for Low Income Housing Tax Credits actually get a 30% boost in their subsidy if they're in qualified low-income Census tracts.