CREATE TABLE table_42763 ("Element" TEXT, "Nuclide" TEXT, "Z  (  p  ) " FLOAT, "N  (  n  ) " FLOAT, "isotopic mass  (  u  ) " TEXT)

What is the isotopic mass (u) when the nuclide is 89 y?
SELECT "isotopic mass ( u )" FROM table_42763 WHERE "Nuclide" = '89 y'
SELECT "isotopic mass ( u )" FROM "table_42763" WHERE "Nuclide" = '89 y'