Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_81 (polling_institute VARCHAR, social_democratic VARCHAR)
### Question:
Which polling institute has a 30.7% for social democratic?
### Answer:
SELECT polling_institute FROM table_name_81 WHERE social_democratic = "30.7%"