Among the customers from Indiana, what is the percentage of their purchased orders in the Central region with no discount?
Indiana refers to State = 'Indiana'; no discount refers to Discount = 0; percentage = divide(sum(Discount) when Discount = 0, count(Discount)) as percentage
SELECT CAST(SUM(CASE  WHEN T2.Discount = 0 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM people AS T1 INNER JOIN central_superstore AS T2 ON T1.`Customer ID` = T2.`Customer ID` WHERE T2.Region = 'Central' AND T1.State = 'Indiana'