CREATE TABLE table_37668 ("Date" TEXT, "Visitor" TEXT, "Score" TEXT, "Home" TEXT, "Decision" TEXT, "Attendance" FLOAT)

Visitor of dallas, and a Date of june 12 had what highest attendance?
SELECT MAX("Attendance") FROM table_37668 WHERE "Visitor" = 'dallas' AND "Date" = 'june 12'
SELECT MAX("Attendance") FROM "table_37668" WHERE "Date" = 'june 12' AND "Visitor" = 'dallas'