Among the customers from Houston, Texas, what is the total profit of their orders in the Central region?
customers from Houston, Texas refers to State = 'Texas' and City = 'Houston'; total profit = sum(Profit)
SELECT SUM(T2.Profit) FROM people AS T1 INNER JOIN central_superstore AS T2 ON T1.`Customer ID` = T2.`Customer ID` INNER JOIN product AS T3 ON T3.`Product ID` = T2.`Product ID` WHERE T1.City = 'Houston' AND T1.State = 'Texas' AND T2.Region = 'Central'