SELECT sum(t2.Total_spent) FROM visitor AS t1 JOIN visit AS t2 ON t1.id  =  t2.visitor_id WHERE t1.Level_of_membership  =  1
What is the total ticket expense of the visitors whose membership level is 1?
CREATE TABLE "museum" (
"Museum_ID" int,
"Name" text,
"Num_of_Staff" int,
"Open_Year" text,
PRIMARY KEY ("Museum_ID")
);
CREATE TABLE "visitor" (
"ID" int,
"Name" text,
"Level_of_membership" int,
"Age" int,
PRIMARY KEY ("ID")
);
CREATE TABLE "visit" (
"Museum_ID" int,
"visitor_ID" text,
"Num_of_Ticket" int,
"Total_spent" real,
PRIMARY KEY ("Museum_ID","visitor_ID"),
FOREIGN KEY ("Museum_ID") REFERENCES `museum`("Museum_ID"),
FOREIGN KEY ("visitor_ID") REFERENCES `visitor`("ID")
);
INSERT INTO  "museum" VALUES ("1","Plaza Museum","62","2000");
INSERT INTO  "visitor" VALUES (1,"Gonzalo Higuaín ",8,35);
INSERT INTO  "visit" VALUES (1,5,20,320.14);