Without more information about the document or data you are referring to, I am able to provide general information about the race categories and the identification of cities in the 1950 Census data.
The 1950 Census form includes the following response options for the RACE variable: “White, Negro, American Indian, Japanese, Chinese, Filipino, Other race”. IPUMS harmonizes and labels these categories as “White, Black/African American, American Indian or Alaska Native, Chinese, Japanese, Other Asian or Pacific Islander, Other race, nec”.
In the 1950 census microdata (available via IPUMS USA), not all cities are identified. Documentation in the comparability section of the CITY variable states that in the 1950 Census, “the city of residence is given for households located in central cities of metropolitan areas only if the metropolitan central city and the remainder of the metropolitan area each had a population of 100,000+ (a total minimum of 200,000+) in 1980. In the 1940 and 1950 samples, a city can only be identified if it was the central city of a metropolitan area. Some metropolitan areas had more than one central city.”
For cities that are identified in the data, all race categories should be available. I took a quick look at the 1950 Census data and see that in many cities, especially smaller ones, there were no respondents in the American Indian/Alaska Native, Chinese, Japanese, Other Asian/Pacific Islander, or Other race categories. Those categories were response options, but were not selected by any of the respondents in that particular sample (I looked at the 1950 1% sample from IPUMS USA). Using full-count data, such as those available for the 1940 Census (and which will be available for the 1950 Census in the future), I suspect you would see respondents of all races represented in a greater share of cities.
The summary file data available from IPUMS NHGIS typically provides greater geographic detail than the microdata in any given sample. However, NHGIS does not provide place-level (city) data tables for years before 1970.