The Publication Manual of the American Psychological Association 6th Edition includes guidance for citing datasets (p. 210-211).
Also, the APA blog includes guidance about citing data sets in your reference list and in-text.
The following database, APA Style CENTRAL, has examples of how to cite datasets. Click the learn tab and search for data.
Italicize the title of the data set.
After the title of the data set identify the type of source ex: [Data file and code book].
If the data set has a doi then list the doi, but if it doesn't then list the url where you retrieved the data.
U.S. Census Bureau. (2012). 2009-2011