CREATE TABLE table_5658 ("Club" TEXT, "Position in 2012\\u201313" TEXT, "First season in top division" TEXT, "Number of seasons in top division" FLOAT, "Number of seasons in Prva HNL" FLOAT, "First season of current spell in top division" TEXT, "Top division titles" TEXT, "Last top division title" TEXT)

Name the average number of seasons for Prva HNL of 17
SELECT AVG("Number of seasons in top division") FROM table_5658 WHERE "Number of seasons in Prva HNL" = '17'
SELECT AVG("Number of seasons in top division") FROM "table_5658" WHERE "Number of seasons in Prva HNL" = '17'