"object" is declared as the primary key of the table and sqlite creates an index automatically for its primary keys. From the sqlite docs at http://www.sqlite.org/lang_createtable.html :
INTEGER PRIMARY KEY columns aside, both UNIQUE and PRIMARY KEY constraints are implemented by creating an index in the database (in the same way as a "CREATE UNIQUE INDEX" statement would). Such an index is used like any other index in the database to optimize queries. As a result, there often no advantage (but significant overhead) in creating an index on a set of columns that are already collectively subject to a UNIQUE or PRIMARY KEY constraint.
Therefore, you need not worry about creating an index manually for "object", it will be managed and used automatically.
Hope that helps,