Table schema:
CREATE TABLE Reservations (Room VARCHAR); CREATE TABLE Rooms (decor VARCHAR, RoomId VARCHAR)

Question: What kind of decor has the least number of reservations?
SQL: SELECT T2.decor FROM Reservations AS T1 JOIN Rooms AS T2 ON T1.Room = T2.RoomId GROUP BY T2.decor ORDER BY COUNT(T2.decor) LIMIT 1