CREATE TABLE table_56840 ("CERCLIS ID" TEXT, "Name" TEXT, "County" TEXT, "Proposed" TEXT, "Listed" TEXT, "Construction completed" TEXT, "Partially deleted" TEXT, "Deleted" TEXT)

What construction has a Listed 09/08/1983, and a Deleted of , and a Name of mid-south wood products?
SELECT "Construction completed" FROM table_56840 WHERE "Listed" = '09/08/1983' AND "Deleted" = '–' AND "Name" = 'mid-south wood products'
SELECT "Construction completed" FROM "table_56840" WHERE "Deleted" = '–' AND "Listed" = '09/08/1983' AND "Name" = 'mid-south wood products'