Database: regional_sales
Question: In which region can you find the stores located in the state whose median income is no more than 30,000?
SQL: SELECT T FROM ( SELECT DISTINCT CASE  WHEN T2.`Median Income` < 30000 THEN T1.Region END AS T FROM Regions T1 INNER JOIN `Store Locations` T2 ON T2.StateCode = T1.StateCode ) WHERE T IS NOT NULL