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_51 (gross_tonnage VARCHAR, entered_service VARCHAR)
### Question:
I want the total number of gross tonnage when entered service was 1903
### Answer:
SELECT COUNT(gross_tonnage) FROM table_name_51 WHERE entered_service = "1903"